Recently, the maturing of electronic device production processes has lowered the manufacturing costs of various electronic devices and led to increasingly compact designs. Moreover, there has been a trend for electronic devices to diversify in function. For example, tablet computers, PDAs, mobile phones, digital picture frames, and other tablet-type electronic devices that are widely used nowadays are generally configured not only for such common functions as data input and storage, computation, communication, and graphical display, but also for displaying multimedia images like those of an electronic book. This explains why these advantageously inexpensive, versatile, and compact electronic devices have been in extensive use, and become indispensable tools, in our daily lives and at work.
Generally speaking, one who uses a tablet-type electronic device to display an electronic book or multimedia file would hold the body of the electronic device with one hand for as long as needed, during which time the user can adjust the inclination angle of the device body by rotating the corresponding arm or wrist in order to view the images displayed on the screen of the device body from a proper viewing angle with respect to the screen. If the force with which the user's arm or wrist supports the device body is adjusted intermittently or is unsteady such that the device body is shaken, the user will be unable to watch and focus on the displayed images, if not feeling annoyed or eye strain, the latter of which may develop into visual impairment. To prevent the aforesaid problems, the user must hold the device body firmly and persistently against shaking while viewing the images, and it follows that the muscles in the hand, wrist, elbow, or arm in use will be tense, rigid, or otherwise uncomfortable.
As a solution, the inventor of the present invention designed a conventional bracket 1 for holding and locking a tablet-type electronic device, as shown in FIGS. 1 and 2. The conventional bracket 1 can be mounted on a plane (e.g., a tabletop) or an object (e.g., a bicycle frame or the dashboard of a car) in an angularly adjustable manner through a supporting leg (not shown) and is provided with a bracket base 10, two horizontally clamping members 11, and a vertically clamping member 12. The bracket base 10 has an inverted T shape, is horizontally provided with a horizontal displacement groove 101 adjacent to its bottom edge, and is vertically provided with a vertical displacement groove 102 adjacent to its center, wherein the vertical displacement groove 102 is perpendicularly connected to and in communication with the horizontal displacement groove 101. The vertically clamping member 12 is vertically movably mounted at a position corresponding to the vertical displacement groove 102. The two horizontally clamping members 11 are horizontally movably mounted at positions corresponding to the horizontal displacement groove 101 respectively. To support a tablet-type electronic device with the conventional bracket 1, the first step is to adjust the distance between the two horizontally clamping members 11 so that the distance matches the horizontal width of the tablet-type electronic device perfectly. The bottom edge of the tablet-type electronic device is then supported in the horizontal displacement groove 101, with the two horizontally clamping members 11 holding two horizontally corresponding lateral edges (e.g., the left and right edges) of the tablet-type electronic device respectively. After that, the vertical distance from the vertically clamping member 12 to the horizontal displacement groove 101 is adjusted to match the vertical height of the tablet-type electronic device perfectly, allowing the vertically clamping member 12 to hold the top edge of the tablet-type electronic device and thereby position the tablet-type electronic device on the conventional bracket 1.
With continued reference to FIGS. 1 and 2, the vertically clamping member 12 is additionally provided with a locking member 13 on the top side to protect the tablet-type electronic device positioned on the conventional bracket 1 from being easily stolen. The locking member 13 is vertically movably mounted on the vertically clamping member 12 and is provided with a lock 14. Once a tablet-type electronic device is positioned on the conventional bracket 1, with its top edge held by the vertically clamping member 12 or the locking member 13, the lock 14 can be locked such that a lock plate 141 of the lock 14 is engaged in a locking hole 121 of the vertically clamping member 12, and in consequence, the locking member 13 enters a locked state, in which the locking member 13 cannot be vertically moved with respect to the vertically clamping member 12 and thus keeps the tablet-type electronic device from separating from the conventional bracket 1. The locking member 13, therefore, ensures that the tablet-type electronic device will not be easily stolen.
The tablet-type electronic devices on the market, however, come in different sizes. Although the conventional bracket 1 can support tablet-type electronic devices within a certain range of specifications, most of the tablet-type electronic devices that fall outside that range of specifications, in particular those whose thicknesses exceed the predetermined range, cannot be mounted and positioned securely on the conventional bracket 1 (i.e., may get loose from or fall off the conventional bracket 1 and be damaged as a result), if they can be mounted at all.
In addition, market research reveals that the conventional bracket 1 has many drawbacks in use, as detailed below with reference to FIGS. 3 and 4.
1. The conventional bracket 1 has two rows of threaded positioning holes 103 adjacent to two opposite ends of the horizontal displacement groove 101 respectively, and each of the two horizontally clamping members 11 is selectively locked to the desired one of the corresponding row of threaded positioning holes 103 by a screw (not shown). When it is desired to support a tablet-type electronic device with the conventional bracket 1, it is necessary to adjust the distance between the two horizontally clamping members 11 until a perfect match with the horizontal width of the bottom edge of the tablet-type electronic device is obtained, and only then can the bottom edge of the tablet-type electronic device be supported in the horizontal displacement groove 101, with the two horizontally clamping members 11 holding two horizontally corresponding lateral edges (e.g., the left and right edges) of the tablet-type electronic device respectively. If the distance between any two selected threaded positioning holes 103 cannot precisely match the horizontal width of the bottom edge of the tablet-type electronic device, the tablet-type electronic device will not be clamped securely and precisely between the two horizontally clamping members 11 and may wobble between the clamping members 11, causing wear of related parts.
2. Referring again to FIGS. 3 and 4, the conventional bracket 1 is so designed that a tablet-type electronic device is positioned thereon mainly by the locking member 13 at the top edge of the vertically clamping member 12 holding the top edge of the tablet-type electronic device. To enable the conventional bracket 1 to hold tablet-type electronic devices of various thicknesses, it is common practice to provide the locking member 13 with a clamping arm 130 of a relatively great length L, which, however, makes it difficult to hold a relatively thin tablet-type electronic device securely and precisely between the clamping arm 130 of the locking member 13 and the horizontal displacement groove 101. If the top and bottom edges of a tablet-type electronic device to be positioned on the conventional bracket 1 are not pressed securely and precisely by the inner edges of the clamping arm 130 and of the horizontal displacement groove 101 respectively, the tablet-type electronic device is very likely to escape from between the clamping arm 130 and the horizontal displacement groove 101 when the conventional bracket 1 is shaken violently, and the tablet-type electronic device may fall to the ground and end up seriously damaged.
In view of the above, it is an important issue for bracket designers and manufacturers to overcome the foregoing drawbacks of the conventional bracket 1 and develop an improved bracket that not only can adapt to tablet-type electronic devices of various sizes, but also ensures that a tablet-type electronic device positioned on the bracket will lie securely and precisely against the inner edges of the bracket, be they the inner edges corresponding to the vertical height, horizontal width, or thickness of the tablet-type electronic device. The goal is for the bracket and the tablet-type electronic device supported thereon to be safely and stably usable in any challenging environment (e.g., over a bumpy terrain, in a vigorously shaking state, or in stormy seas), without the tablet-type electronic device getting loose or escaping from the bracket. In short, the bracket should be able to ensure the safety of the tablet-type electronic device supported thereon and effectively protect the tablet-type electronic device from wear and damage.